help opk? with pic

Shelby
So I took this ovulation test about two hours ago, when I took it the test line was very faint line. I was going to make a chart like I see some of you do with two tests a day and what time to compare to see what day I ovulated. When I went and looked at it a couple hours later 
 t was a positive opk. So is this because I let it sit or because it is a positive opk?